Calibration apparatus, calibration method, and calibration program

Abstract

Calibration data of a photon counting detector consisting of a plurality of detection elements that output detection signals corresponding to photon energies of incident radiation is acquired. A processor is configured to: acquire a plurality of detection signals output from the plurality of detection elements of the photon counting detector in accordance with a predetermined acquisition condition; derive a difference signal representing a difference between at least one representative detection signal that is representative of the plurality of detection signals and the plurality of detection signals; and store the at least one representative detection signal and the difference signal, as calibration data in accordance with the acquisition condition.

What is claimed is: 
     
         1 . A calibration apparatus that acquires calibration data of a photon counting detector consisting of a plurality of detection elements that output detection signals corresponding to photon energies of incident radiation, the calibration apparatus comprising:
 at least one processor,   wherein the processor is configured to:
 acquire a plurality of detection signals output from the plurality of detection elements of the photon counting detector in accordance with a predetermined acquisition condition; 
 derive a difference signal representing a difference between at least one representative detection signal that is representative of the plurality of detection signals and the plurality of detection signals; and 
 store the at least one representative detection signal and the difference signal, as calibration data in accordance with the acquisition condition. 
   
     
     
         2 . The calibration apparatus according to  claim 1 ,
 wherein the representative detection signal is a detection signal output from a representative detection element that outputs a detection signal corresponding to a representative value of the plurality of detection signals.   
     
     
         3 . The calibration apparatus according to  claim 1 ,
 wherein the representative detection signal is a representative value of the plurality of detection signals.   
     
     
         4 . The calibration apparatus according to  claim 1 ,
 wherein the difference signal represents a difference or a ratio between the representative detection signal and the detection signal.   
     
     
         5 . The calibration apparatus according to  claim 2 ,
 wherein the difference signal represents a difference or a ratio between the representative detection signal and the detection signal.   
     
     
         6 . The calibration apparatus according to  claim 3 ,
 wherein the difference signal represents a difference or a ratio between the representative detection signal and the detection signal.   
     
     
         7 . The calibration apparatus according to  claim 1 ,
 wherein the processor is configured to:
 divide the plurality of detection elements into a plurality of detection element groups in accordance with positions on the photon counting detector; 
 derive the difference signal between the representative detection signal and the plurality of detection signals, for each detection element group; and 
 store the representative detection signal and the difference signal, for each detection element group, as the calibration data in accordance with the acquisition condition. 
   
     
     
         8 . The calibration apparatus according to  claim 7 ,
 wherein the processor is configured to divide the plurality of detection elements into a plurality of detection element groups in a channel direction of the photon counting detector.   
     
     
         9 . The calibration apparatus according to  claim 7 ,
 wherein the processor is configured to divide the plurality of detection elements into a plurality of detection element groups including an edge region and a non-edge region in the photon counting detector or a plurality of detector modules constituting the photon counting detector.   
     
     
         10 . The calibration apparatus according to  claim 7 ,
 wherein the processor is configured to derive the representative detection signal of one detection element group included in the plurality of detection element groups based on the representative detection signal of a detection element group in a vicinity of the one detection element group.   
     
     
         11 . The calibration apparatus according to  claim 8 ,
 wherein the processor is configured to derive the representative detection signal of one detection element group included in the plurality of detection element groups based on the representative detection signal of a detection element group in a vicinity of the one detection element group.   
     
     
         12 . The calibration apparatus according to  claim 9 ,
 wherein the processor is configured to derive the representative detection signal of one detection element group included in the plurality of detection element groups based on the representative detection signal of a detection element group in a vicinity of the one detection element group.   
     
     
         13 . A calibration method of acquiring calibration data of a photon counting detector consisting of a plurality of detection elements that output detection signals corresponding to photon energies of incident radiation, the calibration method being executed by a computer, the calibration method comprising:
 acquiring a plurality of detection signals output from the plurality of detection elements of the photon counting detector in accordance with a predetermined acquisition condition;   deriving a difference signal representing a difference between at least one representative detection signal that is representative of the plurality of detection signals and the plurality of detection signals; and   storing the at least one representative detection signal and the difference signal, as calibration data in accordance with the acquisition condition.   
     
     
         14 . A non-transitory computer-readable storage medium that stores a calibration program causing a computer to execute a process of acquiring calibration data of a photon counting detector consisting of a plurality of detection elements that output detection signals corresponding to photon energies of incident radiation, the process comprising:
 a procedure of acquiring a plurality of detection signals output from the plurality of detection elements of the photon counting detector in accordance with a predetermined acquisition condition;   a procedure of deriving a difference signal representing a difference between at least one representative detection signal that is representative of the plurality of detection signals and the plurality of detection signals; and   a procedure of storing the at least one representative detection signal and the difference signal, as calibration data in accordance with the acquisition condition.